The Study On Nondestructive Identification Of Crude Oil Based On Raman-fluorescence Fingerprint

In the offshore oil developmentandthe ocean transportationof petroleum,oil spills will inevitably happen to the environment and ecological security posed a serious threat and destruction.Chemical fingerprintsof spilled oil provide a reliable basis on their identifications.In the oil spill fingerprinting studies,gas chromatography/mass spectrometry,HPLC,fluorescence spectroscopy,infrared spectroscopy,stable isotope mass spectrometry and nuclear magnetic resonance methods.These methods have their own advantages and disadvantages.Raman-fluorescence spectrum is a rapid identification method with a series of advantages,e.g.,non-destructive,high sensitivity,and without special sample preparation.In this thesis,visible light(532nm)and near-infrared light(785nm)are used as light sources for nondestructive extractionandidentificationof the Raman-fluorescence spectroscopy fingerprintsofl 5 kinds of crude oils(the United Arab Emirates,Brazil,Daqing,Kuwait,Liaohe,Sudan,Saudi Arabia,Venezuela,Xinjiang,Iraq,Angola,Oman,Roncador,Viduri and Cinta).By using visible light(532nm)source,the characteristics of fluorescence and Raman spectra are both significantin the crude oil fingerprint.By using near-infraredlight(785nm)source,the Ramanfeatures is significant while the fluorescence spectral characteristics is weak in the fingerprint.Nofluorescencebackground is deduced under the non-destructive extraction of crude oil fingerprint.The two kinds of spectral fingerprints of crude oils are used for blind sample identification with cluster analysis.Chebyshevdistance combined with longest-distance method is regarded as a preferred method for spectral fingerprint clustering.Fisher discriminant analysis is also used for blind sample identification of fingerprint spectra of crude oils.Full model discrimination and stepwise discriminant method are adopted,respectively.Research results can be mutually supportive with the current "oil spill identification system specification" and significantly improve the efficiency of oil spill identification and persuasion,which is important for preservation of the marine environment safe.